1. Field of the Invention:
The present invention relates to an apparatus for feeding paper to the printers used in computers, word processors, plotters, etc., as well as to various other printers.
2. Description of the Prior Art:
Paper having a row of feed perforations or holes along each of both side edges thereof is in many cases used as the paper for recording characters and patterns printed from the printers used in computers, word processors, plotters, etc. The feed perforations are formed at equal intervals on straight lines along both side edges of the paper in positions spaced a predetermined distance from the side edges.
Generally, in this type of apparatus for feeding paper to a printer, one endless belt mounted on a tractor is disposed in the position corresponding to each of both side edges of the paper along the path of the paper fed to the printer. Each of the endless belts are projectingly provided with a large number of feed pins in a row at the same intervals as the intervals of the feed perforations. Each endless belt is entrained between a driving sprocket and a driven sprocket or guide member. Upon rotation of the driving sprocket, the plural feed pins present on the rectilinear portion of the endless belt between the driving sprocket and the driven sprocket or guide member come into engagement with the feed perforations of the paper, whereby the paper is conveyed along the rectilinear conveyance path and fed to the printer.
According to a known apparatus for conveying paper along an arcuate conveyance path and feeding it to a printer, one disk-like feed wheel mounted on a tractor is disposed in the position corresponding to each of both side edges of the paper; a plurality of feed pins are provided projectingly on the peripheral surface of each such feed wheel; and the spacing of adjacent feed pins in the circumferential direction of the feed wheel is made equal to that of adjacent feed perforations of the paper, to convey the paper along an arcuate conveyance path.
In the above paper feed apparatus provided with endless belts, paper is conveyed only along the rectilinear conveyance path, and in the above paper feed apparatus provided with feed wheels, paper is conveyed only along an arcuate conveyance path. In some type of printers, such apparatus are difficult to mount. In both types of paper feed apparatus, moreover, in order to effect stable conveyance of paper it is necessary that at least three or four feed pins be simultaneously engaged with the feed perforations of paper to transfer the driving force of the endless belts or the feed wheels to the paper. In the paper feed apparatus provided with endless belts, such requirement can be satisfied by enlarging the distance between the axis of rotation of the driving sprocket and that of the driven sprocket, while in the paper feed apparatus provided with feed wheels, it can be satisfied by enlarging the diameter of the feed wheels. However, both methods lead to an increase in size of the paper feed apparatus.